1. Field of the Invention
The present invention relates generally to systems and methods for automatic cooking medium control in the well of a cooking apparatus, such as a fryer.
2. Description of Related Art
Known fryers, e.g., open-well fryers and pressure fryers, are used to cook various food products, e.g., poultry, fish, or potato products. Such fryers include a cooking vessel, e.g., a frypot, and the cooking vessel is filled with a cooking medium, e.g., an oil, a liquid shortening, or a meltable-solid shortening. Such fryers also include a heating element, e.g., an electrical heating element, such as a heating coil, or a gas heating element, such as a gas burner and gas conveying tubes, which heat the cooking medium in the cooking vessel. After the cooking medium reaches a preset cooking temperature, the food product is placed into the cooking medium, such that the food product is cooked in the cooking medium. For example, the food product may be positioned inside a product holder, e.g., a wire basket, and submerged in the cooking medium for a predetermined amount of time sufficient to cook or to complete the cooking of the food product. The amount of time sufficient to cook or to complete the cooking of the food product at a given cooking temperature depends on the type of food product which is cooked. Moreover, the cooking medium is used during several cooking cycles before the cooking medium inside the cooking vessel is filtered, replaced, or supplemented with a new or filtered supply of cooking medium.
The cooking medium in an open-well or pressure fryer is maintained at a proper level to standardize or to optimize cooking performance, or both. During each cooking cycle, however, the food product may absorb a small amount of cooking medium during cooking. In addition, a quantity of cooking medium also may evaporate or spill out of the cooking vessel during. Consequently, the level of cooking medium in the cooking vessel may decline or lower over repeated cooking cycles. As a result, the surface of the food product, or the entire food product, may not be fully submerged in the cooking medium when the product holder is positioned within the cooking vessel. This may result in uneven and inconsistent cooking results that reduce the quality of the cooked food product. For example, food product may be undercooked because it is not fully submerged in the cooking medium. Unappealing color variations in cooked food product also may result from temperature variation caused by the food product being exposed alternatively to both the air and cooking medium during the cooking process. Accordingly, it is desirable to maintain an adequate level of cooking medium in the vessel for maintaining cooking quality.
During busy periods, such as the so-called “lunch rush,” it may be difficult for a fryer operator to continuously monitor the level of cooking medium. If a fryer operator notices a reduced level of cooking medium, the operator manually adds cooking medium to the cooking vessel and allows the just-added cooking medium to reach a cooking temperature and consistency before using the fryer again. Thus, the ability to maintain an adequate level of cooking medium depends largely upon the attentiveness and skill of the operator.
Most known level sensing methods, however, are not entirely suitable for use in a cooking vessel, such as a frypot. Float switches, for example, may be fragile and may fail if cooking by-product contaminates the float or float hinge. In addition, such switches often are difficult to clean and take up a significant portion of the cooking vessel's volume. Optical sensors similarly may fail due to contamination from cooking by-product. Further, optical sensors may give false readings caused by reflections from nearby cooking screens or product holders. Capacitive sensors may take up a significant amount of surface area on the cooking vessel surface and must be located in close proximity with one another, which may lead to false readings and makes these sensors difficult to clean. Ultrasonic sensors may be expensive, particularly at the resolution used for monitoring cooking medium in a cooking vessel, and also may be affected by reflections from product holders.